SURVEY OF THE BRITISH ISLES FOR THE EPOCH JANUARY I, I88G. 
327 
Index. 
Page. 
Austen, Mr. Godwin, Palteozoic Rocks be¬ 
neath London.313 
Basalts and Magnetic Attraction .... 312 
Base-station, Kew as.57 
Brough, Mr. B., A.R.S.M., on Use of the 
Magnetic Needle.264 
Bunnahabhain, Comparison or Insiruments at 60 
,, Disturbances at.268 
Canna, Special Survey of.276 
Causes of Local and Regional Magnetic Forces 314 
Central Stations.236 
„ ,, Declinations at .... 240 
„ ., Horizontal Forces . . . 247 
„ ,, Inclinations.244 
Centre of Attraction, Effect on Isomagnetics 262 
Chronometers.61 
,, Rate of. Method of Obtaining 61 
Comparison of Kew and Survey Instruments 58 
Compass Hill, Canna.276 
“Contour Lines” of Vertical Force . . . 285 
Creak, Commander, F.R.S., on Disturbances 
produced by Islands.274 
„ On Local Disturbances.318 
Crystalline Rocks, Magnetic Condition of . 311 
Declination, Diurnal Changes in ... . 65 
„ Specimen Form.71 
„ Secular Change, British Islands 88 
„ „ ,, France ... 90 
,, Observations, Errors of . . . 78 
,, Equation for Calculating . . 240 
Declinations calculated from District Lines . 238 
Defects of Earlier Surveys.55 
Descriptions of Stations. 95-232 
District Curves.240 
Districts, Division of Country into . . . 234 
Disturbance, Diurnal . 64 
Disturbances, Three Classes of.233 
„ Local and Regional, Discus¬ 
sion of.259 
Disturbing Forces, Table of ... . 270-273 
Diurnal Variation and Disturbance ... 64 
Earth-currents.315 
Eastern and South-Eastern Counties, Special 
Swrvey.280 
England and Wales, Results at Stations 133-200 
Page. 
Epoch of Survey.56 
Equation to Isogonals.240 
,, Isoclinals.245 
,, Isodynamics.249 
Equations of Condition, Results obtained by 235 
Errors of Experiment.76 
Evans, Sir F., Isogonals.243 
,, ,, Island of Canna.276 
,, ,, Deduction of Disturbances . 294 
Focus near Reading.282 
,, ,, the Wash.288 
., ,, Kells.309 
France, Secular Change in Dip.87 
Geological and Magnetic Constitution of 
Districts.310 
Greenwich, Annual Variation.81 
„ and Kew, Anomalous Difference 
of Declinations at ... . 281 
Herefordshire Beacon as an Attracting Centre 276 
Highland District, Disturbance Map of . . 301 
Horizontal Force, Diurnal Changes ... 66 
„ ,, Independent Determina¬ 
tions of.73 
,, Specimen Form.74 
,, Errors of Observation .... 78 
„ Secular Change.92 
., Equation for Calculating . . . 249 
Inclination, Diurnal Changes.68 
,, Specimen Form.76 
,, Errors of Observation .... 79 
,, Secular Change.82 
„ ,, ,, Map of . . . 85 
„ Equation for Calculatiug . . . 245 
Independent Results for H. 73 
Instruments.57 
Ireland, Results at Stations .... 201-232 
„ Disturbing Forces in.309 
Isoclinals, Equation to.245 
Isodynamics ,, ,,.249 
Isogonals ,, ,,.230 
„ Effect of Attracting Centre on . 261 
Isomagnetic Lines, Calculation of . . , 233 
,, ,, Terrestrial and True. . 233 
Judd, Professor, P.R.S., on Crystalline Rocks 
in Yorkshire. 313 
